Acoustic emission in sliding friction

Abstract

Acoustic emission associated with friction between two materials is studied. In particular we focus on the acoustic emission signals generated when sliding an aluminium block on sand paper. We show that energy and amplitude of the individual signals (hits) are distributed according to a combined probability law. Most energies and amplitudes are power-law distributed and fewer are Gaussian distributed. It has also been found that decreasing the roughness of the sand paper displaces the Gaussian distribution to larger energies and amplitudes. The overall scenario can be explained in the framework of the Dragon King Theory, that suggests that extreme events follow a different physical law than those in the main distribution